Select the correct choice below and fill in any answer boxes within your choice. A. The function is concave up on nothing and concave down on nothing. (Type your answers in interval notation. Use a comma to separate answers as needed.) B. The function is concave down on (negative infinity comma infinity ). C. The function is concave up on (negative infinity comma infinity ). Select the correct choice below and fill in any answer boxes within your choice. A. The function has an inflection point at nothing. (Type an ordered pair. Use a comma to separate answers as needed.) B. The function does not have an inflection point.